Translucent impregnated paper photographic plate



United States Patent Oflice 3,394,391 TRANSLUCENT IMPREGNATED PAPER PHOTOGRAPHIC PLATE Charles M. Wiswell, Westbrook, Maine, assignor, by

mesne assignments, to Scott Paper Company, a corporation of Pennsylvania No Drawing. Filed Mar. 29, 1967, Ser. No. 626,719 8 Claims. (Cl. 96-46) ABSTRACT OF THE DISCLOSURE A translucent photographic member or plate is made by impregnating a suitable paper-web with a solvent solution of a resin binder, color-forming chemicals and a lower haloalkane photosensitizer and evaporating the solvent. The color forming chemicals are preferably a furfurylidene and a primary aromatic amine, and the sensitizer is preferably iodoform. The translucent plate is particularly useful for receiving a microfilm enlargement after which it can be used as a master to make additional conventional diazo copies by contact printmg.

RELATED APPLICATION This application is related to Ser. No. 351,316, Photosensitive Medium Comprising a Furfurylidene, a Prirnary Aromatic Amine and a Lower Haloalkane, filed March 12, 1964, by Mattor and Price and abandoned in favor of its continuation-in-part application Ser. No. 641,720, filed April 21, 1967.

BACKGROUND OF THE INVENTION The above-identified application discloses a novel photographic medium comprising a resinous binder, usually in the form of a thin supported film containing dispersed therein a furfurylidene, a primary aromatic amine and a lower haloalkane photosensitizer. Upon being exposed to light, the haloalkane activates the furfurylidene and primary aromatic amine which, when subsequently heated, react to form a color body. The photographic member can be developed quickly by heating it above about 100 C., which heating also drives the haloalkane sensitizer and also preferably the amine from the background areas so that they are stable and no longer photosensitive.

Other color precursors that are activated by a photosensitive lower haloalkane and heat to produce a color body have been used to replace the furfurylidene in the above system. Three sulfenyl chloride derivatives, i.e., the sulfenamides and the dithiadiazines and certain protected aldehydes, i.e., aromatic cyclic acetals, have performed satisfactorily.

THIS INVENTION It has been now found that such photographic mediums can be used to impregnate an absorbent paper web to produce a novel photographic film or plate that is translucent to the eye but essentially transparent to and activated by ultra-violet radiation. Such a plate is particularly adapted to being imaged by an ultra-violet light microfilm enlarger. The quality print thus obtained can be then used as a master to make additional conventional low cost diazo copies by contact printing. It is difficult to directly make acceptable diazo copies with such an enlarger because of the loss of resolution.

3,394,391 Patented July 23, 1968 PREFERRED EMBODIMENT A suitable body stock is 28 pounds per ream (3300 square feet) paper sheet made from about equal weights of moderately beaten hard and soft wood fibers, and moderately sized, e.g., with 0.1 pound of Aquapel (Hercules trademark) per ream, but substantially free of clay fillers.

The paper web is impregnated with 4 pounds per ream (dry basis) via Mayer bar application with the following formulation (parts by weight):

Formula I Iodoform 200 Difurfurylidene pentaerythritol (compound I) 200 l-chloro-2,4-phenylenediamine Polyphenylene oxide (General Electrics PPO) 400 Chloroform 7170 The impregnated sheet is air dried at 30 C. in the dark or under a yellow safe light. It is then imaged with a UV. microfilm enlarger (Caps Equipment Model No. Mark I) for 20 seconds at 16 X enlargement, following which it is developed by heating to 300 F. in air for 30 seconds. An excellent brown image is obtained. Diazo copies are then made in a white print machine (Reproduction Engineering Corporations Model No. 842-M5) with the normal setting.

The following formulations can be used to impregnate the paper web in about the same weight amount.

Formula II 2-p-dimethylaminophenyl-S (4 dimethylamine)- benzylideneimino 1,3 dioxane (Compound II) g 0.04 4-chloro-m-phenylenediamine g 0.06 Iodoform g 0.10 Polystyrene Resin (Dow PS3) g 0.40 Chloroform ml 4.0

(Yields a yellow image on white background.)

Formula III 2 (4 di-methylamino)phenyl 5 methyl-S-nitro- 1,3 dioxane (Compound III) g 0.04 4-ethoxy-m-phenylenediamine g 0.06 Iodoform g 0.10 Polystyrene resin g 0.40 Chloroform ml 4.0

(Yields a deep brown image on white background; replace amine with 3,3-dimethoxybenzidene to obtain a (Yields brilliant green image.)

, 3 CHEMICAL STRUCTURES Compound 1 Compound II Compound III IT: H30 0 Compound 1V Compound V Compound VI Formula VI (Yields strong blue image.)

Any suitable uncoated light weight evenly absorbent paper web can be used. Preferred ream weights are in the range of 30 to 40 pounds. Paper of the type called carbonizing tissue made as a base for the common carbon paper used in typewriters has been found to be satisfactory. Usually the webs will not be filled with clay or silica fillers, although small amounts can be used in some cases. The web will normally be impregnated within the range of 2 to 7 pounds per ream (dry basis) of the solvent solution of the photographic chemicals.

The resin binder used as preferably a film-forming one that in a free state forms a translucent to transparent film that is colorless or substantially colorless so as not to interfere with or mask the color produced by the photographic chemicals. Some polyester polymers have been found to be unsatisfactory presumably because the hydrogen iodide attacks the ester linkage. Polymers containing large amounts of hydroxyl groups will usually interfere with image formation. Polymers that are suitable are the solvent soluble polystyrenes, polyphenylene oxides, polyterpenes and methyl methacrylates.

The solids content of the impregnating solution is adjusted to give the desired viscosity and will normally be in the range of 10 to 20 weight percent. The resin will usually amount to 1 to 40 parts by weight on the colorformer and the sensitizer will be used in an amount of 0.1 to 20 parts by weight on the color precursor. The primary aromatic amine will be used in an amount in the range of 0.1 to 4 parts by weight of the color precursor chemical.

What is claimed is:

1. A negative-working translucent photographic member comprising a thin paper web of cellulose fibers impregnated with a light-passing resinous binder containing dispersed therein in photographic amounts and proportions a furfurylidene as a color former, a primary aromatic amine enhancer therefor and a lower haloalkane sensitizer.

2. The member of claim 1 wherein said web is uncoated, has a ream weight in the range of 30 to 40 pounds per ream (3300 square feet) and is free from any appreciable amount of a particulate filler.

3. The member of claim 1 wherein said furfurylidene is difurfurylidene pentaerythritol, said halohydrocarbon is iodoform and said primary aromatic amine is a 1- chloro-2,4-phenylene-diamine.

4. A method of producing an enlarged copy from a microfilm original comprising exposing from a microfilm original through an enlarger a translucent photographic plate comprising a thin paper web impregnated with a resinous binder containing dispersed therein in photographic amounts and proportions a color forming chemical selected from the group consisting of the furfurylidenes, the sulfenamides, the dithiadiazines and the aromatic cyclic acetals, a primary aromatic amine enhancer therefor and a lower haloalkane sensitizer thereof, developing said photographic plate by heating the same to a temperature above C., imaging a photo sensitive sheet through the developed photographic plate and processing thus imaged sheet to obtain a permanent image.

5. The method of claim 4 wherein said color forming chemical is a furfurylidene.

6. A method of preparing a translucent photographic plate comprising impregnating an unfilled thin paper web with a solvent solution of a resin binder, a furfurylidene, a primary aromatic amine and a halohydrocarbon light sensitizer in amounts and proportions adequate for image formation, and drying the same in the absence of light that would cause a photo-chemical reaction.

7. A translucent photographic member comprising a thin paper web impregnated with a light-passing resinous binder containing dispersed therein in photographic amounts and proportions a lower haloalkane photosensitizer that produces an acid radical upon excitation and a color precursor that is activated by said acid radical and by subsequent heating to produce a color body said color precursor being selected from the group consisting of solvent soluble furfurylidenes, sulfenamides, dithia-diazines and aromatic cyclic acetals, and a primary aromatic amine enhancer.

8. The photographic member of claim 7 wherein said color precursor is a furfurylidene.

References Cited UNITED STATES PATENTS 3,140,947 7/1964 Foris 96-48 NORMAN G. TORCHIN, Primary Examiner. R. H. SMITH, Assistant Examiner. 

